狩猟戦旗バトルアレンジver Extended to 20 minutes+
This is just the arrangement version of the main theme, either way, it still good, even though I still prefer the main theme more than this
Other Shironeko Project extended BGM:
https://www.youtube.com/playlist?list=PLJSFfiBIf4LDlQUpy154dNJiRqeVQaZA3.